Insulation, Radiant and Vapor Barriers - Expert Opinions Wanted

My wife and I bought a fixer-upper a couple of months ago and now that I've gotten the house operational, it's time to start the fixing-upping and because I'm going to take advantage of both the Home Depot and Lowes 10%-off, one time deals; I intend to buy most everything in two monstrous trips, therefore I could use a little help with my timetables and getting a better understanding of the projects;

So, if some "experts" could take the time to express opinions on a few subjects, I would be forever grateful...

1) I'm going to blow cellulose onto the unfinished attic floor; I'm under the impression that there would be no problem, if I were to wait until after I replace the wiring to blow the insulation, this would both be easier and would create no hazards; Am I correct in this understanding?

2) All of the figures about insulating attics make reference to "unfinished" space, but I can't find much of anything about "finished" space;

Right now, there's nothing up there except some FG batts which are nowhere near the correct R-value; I'd like to put some wafer-board over at least some of the attic for added storage; I'm confused over whether or not this would turn the space into "finished"; Somewhere, I've read that if you were to put a floor down, you should leave an inch above the insulation for air-flow; First of all is this inch figure correct? And, should I treat the floored space any differently than the unfloored? Or am I correct in my assumption that I can just map-out what will be floored, extend the affected joists upward with a 2"x4" frame if needed, fill in the proper number of inches of cellulose, leaving an inch for air-flow at the top and nail the waferboard down to the frame?

Or, should I do something completely different?

3) My exterior walls are all made from concrete block; They are covered on the outside with stucco and if the inside isn't actual stucco, it's a reasonable facsimile; But any way you look at it, none of my exterior walls are insulated and this winter, they are all cool to the touch;

I'm planning to cover the interior of the exterior walls with foam board and cover the foam board with some thin sheetrock; One of the over-riding goals of this project would be to not lose any "extra" square footage in the insulation exercise; Initially, I figured that I'd screw down some furring strips, then fasten the foam board and the sheetrock to these strips; But now I've read to glue the foam board between the furring strips and then, screw the sheetrock to the frame...

What would be the preferred method of the experts?

4) And because undoubtably, someone is going to suggest the radiant barrier paint additive as a way to lose no square footage; When you are making such a suggestion, if you could explain how a ceramic coat would conduct less coolness than the existing concrete block; I would appreciate it; My understanding is that the paint reflects the artificial heat inward and unless I'm confused, my walls are wicking cold in from the outside and I can't see how the ceramic would make any difference...


Thanks in Advance;
And please be on the lookout for follow-ups;
Plus, I apologize for the disjointed nature of this post;

Thanks again;
R

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http://www.ornl.gov/roofs%2bwalls/facts/index.html This is a Dept. of Energy site that provides facts sheets on building performance applications. The 2 that will be of interest to you are "Insulation Fact Sheets" and "Radiant Barrier Fact Sheets".

I'm going to discuss principles that apply to different applications because without understanding what is occurring, you cannot take preventive action. You mentioned wicking up cold and the masonry wall being cold. The 2 are known as capillary action (wicking) and the other is diffusion (cold wall). Both are heat transfer mechanisms concerning conduction. Heat reflection in any direction is radiant heat transfer. And lastly the 1 inch space between the insulation and the floor creates a convective loop in a confined space and concerns convective heat transfer.

All 3, conduction, radiant and convection are present concerning heat loss or gain. The dominant heat transfer mechanism during the winter is diffusion (conduction) and the dominant heat transfer mechanism for the summer is radiant. Understanding that all 3 are present regardless of season but one is far more important than the other 2.

What I am about to explain has to do with moisture control when applying insulation. Do not confuse this with the aforementioned, though the application remains the same. Whenever you heat air inside your home, that air expands and it creates pressure that pushes outward from inside the home. Pressure has a greater affect on the water vapor molecule than it does with heat concerning permeating materials, like insulation and masonry walls. This is because nearly all the materials in a home have thermal properties. Which mean it slows down the heat flow. But the moisture flow is being accellerate because of the pressure applied to it. The way this is done usually by diffusion and capillary action, just like in conduction. There is concern today about convection. The creation and expansion of the air sealing industry exemplifies this, but that is a different subject.

Different materials, like masonry, can absorb moisture quickly and release it slowly. While other materials, like figerglass absorb moisture slowly and release it quickly. Density of similar materials can have the same effect. For example, cellulose is wood fiber and so is wafer board, but their densities are different. This will affect the rate in which each material will absorb and expel moisture. When the 2 materials touch each other when applied to an attic floor, the probability of condensation occurring is much higher than if the 2 did not touch each other. The probability of moisture increases when dealing with disimilar materials, like masonry and any type of insulation. That 1 inch gap you were referring to between the wafer board and the insulation in the attic is known as a drainage plane and it dramatically decreases the probability of condensation occurring between the 2 different materials. This also applies to your masonry walls.

A few years ago I was asked to investigate 1,000 complaints concerning remodelling that resulted in structual damage because of moisture. One would think roofs, right. Not one was about a roof. When interviewing homeowners, the vast majority at least 800 out of the 1000, said they checked references, the BBB and observed previous work by the contractor. When interviewing the contractors, each and everyone of them said, 1000 out of a 1000, "These people don't know what they're talking about.", "I do good work.", "They were asking me stupid questions all the time." and the best yet was "I'm been doing this a long time and I never had a problem."

Technology in the building industry has increased dramatically over the last few years. Making structures more energy efficient means that they are tighter than years ago. For example, 30 years ago the average air exchange in a home was more than 3 per hour. Today, it's less than 1 per hour. The 3 air exchanges per hour extracted the moisture for the home and took it away. In some cases you didn't even need attic ventilation.

An example concerning moisture damage is www.eifs.com This involves hundreds of millions of dollars worth of damage to structures throughout the U.S. if not $Billions. What was the cause of this problem? Could it be the failure to install a rain screen (Tyvek), drip screen (flashing at the bottom of application), caulking failure at protrusions and transitions? How about ignoring the rule that any material applied to the outside of insulation that has a vapor barrier should have a 5 times greater perm rating than the vapor barrier (5 to 1). By the way this is called the Marriot syndrome because it was first exposed at one of their hotels. These are all simple things that could have avoided this damage. You don't have to be a physicist, you just have to follow the rules.

Understanding what occurs when you apply something like insulation to your home will help you avoid problems in the future. Be it a wall, attic or floor.

resercon; I really appreciate the thorough explanation and I sincerely hope you had the response on file and didn't actually type in all that valuable info just for me;

I'll take a look at your specific url; I've been up and down DOE's website, but on your suggestion, I'll read the recommended info this evening and I'm sure I'll probably need to post a follow-up; I hope you don't mind.

But from an initial reading of your post; I should say that the cement block is cold from diffusion and it looks like my idea of framing up for waferboard in order to get the one-inch overhead is the way to go; Are you also saying that I should put an inch between the foam board and the block walls?

Moisture really isn't a problem in the desert; As I initially posted, I originally planned a half-inch furring board as a frame underneath the foam board and the sheetrock; But the only related instructions I could find online were for basement walls on homedepot.com and they are the ones who suggested gluing between the strips; If I'm reading you right, I should go back to my original plan but make the furring strips an inch? Is this interpretation correct?

Once again; Moisture really isn't a problem; There are cactuses in the yard and we get an annual rainfall of around nine inches in the years without drought; I re-read your post and the suggested url after dark and I'll probably have a follow-up;

Thanks for the info;
R

In your area vapor barriers are not even recommended because of the low levels of humidity. There is a great debate on the proper application of vapor barriers and methods to avoid moisture problems in homes in this country. My view is based on the following.

In areas where heating is used during a part of the year, most people are comfortable with temperatures at 70 degrees and with a relative humidity of 40%. Regardless where they live. In areas where low humidity is common, humidifiers are used to increase the relative humidity in the heat in their homes. It is not uncommon to only be able to reach 25% relative humidity in these areas. So people become innovative and creative when it comes to comfort in their homes. They begin to introduce things into the home that are moisture producing, besides the things that already are present, like cooking, showering, washing and drying. For example, drying fire wood inside, plants, pets like dogs who produce 5 pounds of humidity a day, fountains and much much more.

Relative Humidity is expressed in a percentage to a specific volume of air at a certain temperature. This is because in warm air the molecules separate and gives it the ability to hold more water vapor molecules than cooler air because as the air cools, the molecules come closer together and it can hold less water vapor molecules as a result.

Let's assume a certain volume of air at 70 degrees has 23 grains of moisture in it and has a Relative Humidity of 40%. The temperature of the air drops to 40 degrees, the 23 grains of moisture is the same but the Relative Humidity is now 80%. This supports that heat condenses on cooler surfaces. It also explains why a cold soda can sweats in the summer and a hot cup of coffee doesn't. It also explains why the air is so dry in homes during the winter. As you raise the temperature of the air in the home, you reduce the relative humidity in the air.

I agree with the furring out then applying the insulation and sheet rock. I base my opinion on moisture producing applications in a heated homes to achieve desired comfort levels, insulation and vapor barrier do not stop flow, they slow it down. Which means that there is a constant flow of heat with a percentage of moisture going through the materials. And the different rates of absorption and expulsion of moisture the different materials in the wall possess. This gap or drainage plane between the materials is a buffer that allows for a TIME delay for the transfer of moisture from one material to another. This also applies to your attic floor.

Once again, I thank you for your response and the thought which you've applied to your answers; I still haven't gotten a chance to revisit the DOE site; I took advantage of the holiday to get some of those things done that a stay-at-home dad can't do, when his wife is at work and I'm being tailed by a two year old; Every time I try to climb on the roof when my wife is at work, inevitably the two year old will climb up the ladder behind me and then, if she doesn't fall which she did once, she starts crying because she needs help down; So I'm sure you understand, because my wife was on holiday, I spent the day between the roof and the crawlspace trying to get as much accomplished, as possible.

But if you don't mind, a point of clarification; Would you advise me to furr-out an entire inch, or could I get by with the 1/4 inch strips?

I'd like to get the best return for my expense and effort; Though, resale value is actually a bit more important than energy-savings; Energy-savings does effect resale value, but so does square footage and the like;

So, based on your experience; Would you advise me to put a full inch between the foam and the block, or could I get by with a smaller measurement?

Thanks again;
R

There are several concerns with using a 1/4" wood slat. The first is that you will not have enough wood to nail into, to secure the insulation and sheet rock to the wall. There is also movement between different materials in the home, even though they will not be load bearing the masonry wall is. Because of the low humidity in your area the 1/4" would be fine except for the aforementioned.

If you go with a 1 x 2 inch slat, if you take a measurement of the thickness of the slat, it is only 3/4th inch thick. Even at that thickness you couldn't use nails to secure the sheet rock over insulation. You would have to use screws and the slats would have to be well secured to the wall. I would suggest masonry screws 10 to 12 inches with an adhesive.

For the drywall screws be sure to calculate the thickness of the wall to determine the length of screws. You want as much as possible of the screw into the slats without touching the masonry wall. And remember the drywall screws are supposed to sink into the drywall a little.

OK - Now I feel like an idiot; I'm sure glad you intervened and I didn't order a bunch of boards which would give me nothing on which to fasten the covering... Duh, I feel like a fool...

Thanks again for all your help; Your informative posts, easy to understand reasoning and common sense when it comes to furring strips; You've been more help than you may realize and for that, I thank you.

Now, if I could just find something that'll give me more than an R-5 for each inch of thickness; I'm going to keep looking at the various manufacturer sites, review my copy of Mother Earth News with the info about alternative materials and some additional how-to info before I may come back at you and this forum with some other, hair-brained scheme to keep from losing too many inches in the process. (Furring strips/Foam board/Sheetrock/Radiant Barrier Paint Additive?)

But based on the explanations which you have posted, I feel that I'm much better equipped to consider my options and because I'm actually planning to take about two weeks to finalize my shopping lists; I still have a little time...

I'll leave you with one last question which you are welcome to completely ignore, if my assumption is correct, or you feel confident that a cost-comparison will not come out to be the most efficient use of my resources.

Since I'm going to cover the plaster with the decided-upon insulating layer and I'm going to cover the plaster ceilings with sheetrock in an attempt to cover decades of wiring repairs and where the previous owners took out a couple of walls and installed a couple of vent pipes; If a cost-analysis proves that I can more inexpensively add foam beneath the ceiling rock than I can frame-up the attic in order to floor part of it and get my inch; Would there be a problem, if I were to follow the same procedure we have developed for the walls onto the ceiling? After all, with these 10' ceilings, I actually have headroom to spare...

Once again, if you can see no problem with this secondary plan, or if you are confident that the price of this fix would come out to be more expensive than the "extra" bags of cellulose for the attic and the price of the 2"x4"'s which I'll need to frame the joists up; Please feel free to ignore my last query.

After all, you've been more help than I could imagine and for that I thank you from the bottom of my heart.

1. to heck w/ blown in insulation. if you can get in your attic do it yourself. save money. your ceiling joists should already be insulated. if not save yourself about 2,000.00 and go to the depot and buy the recomended r-value for the width of your ceiling joists and do it youself. why pay a guy who knows as much as you who is getting paid as much as me to do something YOU can do. as long as you install properly(cut to fit, dont force it in there insulation performs best when cut to fit. in other words, dont put a 24" bat in a 18" cavity.
2. if your not gonna live in the space dont sheath the whole floor. let it breath. dont even nail down your sheets of plywood, just overlap
if you have an attic, your ceiling for the floor below should be the only insulation between that and the ridge(cathedral ceilings does not apply)

http://resercon.com/msgboard.mv?parm_func=showmsg+parm_msgnum=1000065 This is a reply I gave about heat load/gain calculations on my message board. It gives the basic formula for heat load/gain calculations, which means all that load/gain programs are derived from this equation. The post illustrates the importance of R-value when considering heat loads for the home. You might be pleasantly surprized by my response.

R-value with insulation is a representative expression. For example, R-19 means 1/19th of a BTU transmits through a specific square foot material per hour. So if I had insulation that was rated at R-19, each square foot of the insulation would lose 1/19th of a BTU per hour. We can deduce from this that an R-1 is 1, R-2 is 1/2, R-3 is 1/3 and so on. We can also deduce from this that the greatest saving with insulation are on the low R-values. Because there is a 50% savings from R-1 to R-2, a 25% savings from R-2 to R-3, a 12.5% savings from R-3 to R-4 and so on. This supports the statement of the "Law of Diminishing Returns" concerning the cost effectiveness of adding insulation.

Also when considering cost effectiveness concerning insulation a major factor is surface area. This is also illustrated on my message board concerning the amount of heat required to maintain a desired temperature per hour. Let's consider walls verses attic and assume a home that is 30 feet by 30 feet with a 8 feet high ceiling. The square footage of the ceiling is 30 x 30 = 900 sq. ft. The square footage of the walls are 30 x 4 walls x 8 high = 960 sq. ft. However there are no windows and door in your ceiling and you have to subtract them from you wall area to get your net wall area. Let's assume there are 10 windows that are 12 sq. ft. each (10 x12 = 120 sq. ft.) and 2 doors that are 20 sq. ft. each (2 x 20 = 40). To get the net wall area you are going to insulate is 960 - 120 - 40 = 800 sq. ft. which is less square footage than your attic. When we also consider the bouyancy of heated air and the cost per sq. ft. to insulate an attic, without question, it is far more cost effective to insulate your attic than your walls. It does not mean you should ignore your walls.

What it does mean is that you have to be more practical about it. The R-5 you intend to apply to your walls in my opinion is sufficient. It is nice to have more but if it cost you considerably more to do or make it more difficult to apply, then it's not worth it. For the attic, add more insulation and if you are worrying about the gap or drainage plane, install 1 x 2 slats perpendicular on the floor joists and and put your wafer boards on top of that. A lot easier and less expensive than dropping your ceiling.

Thanks again for the response;

The original plan for the attic remains being to blow some of that cellulose that you get along with the rented blower from Lowes in between and I guess over the joists; DOE suggests an R-38 based on my zip code and though I seem to have lost where I wrote down the web address off of the package and apparently "Cocoon" has changed their url since any of the lists I can find, last updated; My hippie magazine says that loose-fill cellulose comes out to an R-3.5 per inch of thickness and that sounds about right to me.

So based upon that figure, it'd take 11.875" of cellulose in order to achieve an R-38 and if I were to simply fill-up the joists, I'd only get an R-28 and no inch.

Right now, there's a single layer of rolled fiberglass up there, between the joists; It's looks relatively new, most likely it was installed when they did the roof, four or five years ago and though I honestly haven't pulled it up to look at the label; I'm guessing that it's most likely, a single layer of the R-11 you can buy locally; After all, everything in this house was bought locally and as I go through fixing things, I can pretty much determine from which store it was acquired, because after all this is a small town... And I should also point out that approximately a third of the house has no ceilings, therefore no attic and when you are in the unfinished addition, you look up and see the bottom of the actual roof; Though, they did only take the walls up to where the ceiling would go, so I've got a lot of freedom to change things, but that's another story.

Before I cement my plans, I will go up and see exactly what R-value is already installed; Though, I should also say that my research indicates that it would be better to pull-up the existing insulation, blow-in the cellulose and because I'm sure, based on the other repairs which have been done to the home, the insulation isn't fastened down in any way; I hope and plan to salvage it for reassignment over the crawlspace instead of laying it back over the joists, but that remains to be seen and will be determined by careful examination of the actual insulation and how it might stay together for the trip from top to bottom.

Right now, there's nothing under the floors or over the crawlspace just as there is nothing in or over my walls.

I'm a little torn about what value I should work towards concerning my walls and crawlspace; At this moment, I have gas heat, but another project that I'm prioritizing is ripping out the inefficient gas heaters, along with the electric baseboards that I don't use and the electric wall heaters, plus one of the freestanding fireplaces which looks and acts like a big wood stove and replace it all with a heat pump; Most likely geothermal, but the jury is still out on the actual type of heat pump, as of yet. But anyway you look at it, DOE has a fairly wide variance between the recommended values on the walls and over the crawlspace depending on the type of fuel used. Though, since I'm planning to redo the heaing and add cooling in early summer, I guess for simplicity the heat pump figures should be my goal.

But, I'm also of the school that something is better than nothing; So as of right this minute, I'm thinking that I may just put the R-5 on the walls; Though, if I could get enough assurances that someone makes polyisocyanurate in an environmentally friendly enough manner to satisfy my wife and if it proves to be less expensive or comparable to the alternatives, I'd consider it but those are two very big "if's".

Under the floor, I should have no problem taking it up to an R-25 which is what is recommended for a heat pump in my zone; But, I may just start with the R-11 that I might possibly be able to recycle out of the attic until I've finished replumbing the house which most of the supplies have been prioritized into the second buying spree, currently scheduled for mid to late spring;

Right now, the plan is to tackle the wiring most of which comes up from and will come from the crawlspace; Install some insulation in the areas without plumbing and then fill everything out with however much I can install efficiently and neatly when I'm ready to declare the bottomside complete. But, I see no reason why I can't take it to an R-22 to an R-26 (How mathmaically would one get to 25 - Rhetorical question, more than anything else); So in actuality, my walls will be the only thing lacking according to the DOE and that's why I'm still considering loosing the added inches around the perimeter and researching the possibilty of polyisocyanurate for that additional oomph.

Of course, because there's three and a half inches of stucco on the outside of my eight inch block and existing plaster on the inside; Plus the two and half to three and half inches that I'm talking about adding to the interior, along with another layer of stucco which is scheduled for year three; So in reality, we're talking about walls which will be about sixteen inches thick when all is said and done; So, I wouldn't even be considering loosing the additional inch, if I weren't so hung-up on appraised value in order to more fully take advantage of the relocation program administered by my wife's employer.

But that's another story...

As to my thought about trying to get a five on the underside of the ceiling; I am going to sheetrock the ceiling anyway and I do have 10' ceilings in the finished part of the house, so I've got room to spare and that would make the frame-up more manageable; Especially, if it proves cost-effective to double-up on the underside taking it to a 10; But that'll take more research about the pros and cons, plus I'll need to draw some lines to see how it'll look and study how a doubled layer would effect the existing closet doors.

Thanks again for the response and thanks for letting me vent; I think I'll put a post in the Home Selling forum in an effort to figure-out how precisely, insulation to DOE recommendations would effect the appraised value...

Keep warm and well insulated;
R

PS) Thanks for your mathmatic equation and the explanation of diminishing returns; I certainly made me feel better after I was literally shocked by how expensive it is to heat this house in the middle of the desert...

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Archive Info
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The various threads which helped develop my plan of action (Walls) are all linked from
the following discussion which also contains climatic data specific to my locality;
http://forum.doityourself.com/showthread.php?s=&threadid=126545

When it comes to cost effectiveness of energy conservation measures and environmental impact of associated products, in certain circles I am considered an expert. And it is not just because I do this for a living. My views concerning Energy Efficiency (EE) and Renewable Energy (RE) programs are considered controversal not only by collegues but by many notable organizations in this country.

With that said, what I'm about to say you will not hear too many Energy Conservationists say this. But it is the truth. Geothermal Heat Pumps are not environmentally friendly. Your present gas furnace is more environmentally friendly than the most expensive, less expensive to operate Geothermal Heat Pump in the world. The 1st and 2nd Law of Thermal Dynamics support the theory of "Thermal Bottlenecking". What this states is that for every BTU you use for heating or cooling a fossil fuel power plant burns 3 BTU's. Or if you prefer, 3 times more pollutants released into the atmosphere. There are those who misguidedly will argue the Coefficient of Performance (COP) of 3 with heat pumps equalize this inbalance. Regardless of the efficiency of the unit, the 3 times more rule still applies.

The Federal Government mandates that new heating systems must have an 80% Annual Fuel Utilization Efficiency (AFUE) rating. They also mandate that fossil fuel power plants in this country must meet Federal Standards on emissions. I got news for you, those standards are no where near 80% AFUE. Not even close. You want to know why Lobbyists and Pubic Relation people make so much money? Can you imagine if we put that much money, intelligence, talent and effort towards the environment?

This exemplifies how much we are misled concerning energy conservation and cleaning the environment. To the extent that it influences our decisions to do things that are the exact opposite that we wish to accomplish. I'm not just talking about heat pumps, I'm talking about everything.

My ability to reduce energy bills and increase comfort is well documented. There is a profound positve impact on the environment as a result. What separates me from collegues is the word "practical". I don't need to spend thousands of dollars to save a few. Neither do you.

Practical to me means, reducing your energy costs, while increasing your comfort, at the same time making things safe with more than adequate air quality, increasing the value to the home and having an impact on the environment for less than a $1,000. Impossible? In most cases yes, because it is not me that has to change attitudes.